The Lucas mechanical fuel injection system was fitted to the Triumph TR5, TR6 and Triumph 2.5PI. The electric petrol pump made by Lucas is often said to be a source of trouble and is therefore replaced by Bosche unit. The centre of the system is the metering unit which is driven off the distributer drive of the engine.

diagram of a Lucas Petrol Injection system

Diagram to show the layout of components in a typical Triumph PI system TR5 and 2.5PI Estate.